Ultrasonic Control of Algae in Stormwater Systems

Large concentrations of algae pose immediate water quality issues. Water quality issues posed by the presence of large concentrations of algae include: decreased water clarity, increased suspended solids, reduced dissolved oxygen levels, altered pH levels and in some instances production of deadly toxins. Controlling algae in stormwater systems helps to prevent this degradation of water quality and reduces the rate of sediment build up while also providing aesthetic improvement.

Recently ultrasonic resonance has been successfully applied to control algae in many different applications including stormwater ponds. A specific “blend’’ of ultrasound frequencies and a relatively low amplitude, or output power (W/cm3 ) is used to selectively target and destroy the cellular structure of different types of algae.

Benefits of the technology include low energy consumption and maintenance requirements. In addition, the device is very environmentally friendly with no adverse effects on humans, plants or animals with the exception of aquatic organisms that have hearing ranges within the frequencies used.

Previous research on both high and low power ultrasound to control algae are reviewed. A need for more peer reviewed research on the subject to be published is identified; specifically with respect to species tolerance levels and optimal frequencies.